1. Field of the Invention
The present invention generally relates to semiconductor memory and specifically to systems and methods that allow for varied write throughput in semiconductor memory applications.
2. Related Art
Flash memory is a non-volatile memory composed of a number of individual memory cells that can each hold a value (i.e., 1 or 0) depending on what has been written to them previously. Like most re-programmable memory, Flash memory can be read, programmed, or erased. To program and erase Flash memory requires the application of a certain amount of current (often provided by a charge pump) to the cell or cells that are to be programmed or erased. The number of cells that can be written at a time is called “write throughput.”
The amount of write throughput that a memory device can accommodate depends on a number of factors including the size of the memory array and its structure, area allocated for peripheral circuitry (e.g., charge pumps, regulators, drivers, etc.), operating temperature, and power supply voltage, to name a few. One of the largest factors affecting write throughput, however, is the current capacity of the charge pump, which is directly related to, amongst other things, the voltage level of the power supply.
Memory devices (as with most semiconductor devices) are typically designed to operate using a range of supply voltages. For instance, one common supply voltage range for such devices is 2.6 V to 3.6 V. In order to guarantee a particular throughput for a memory device, the memory device must be designed to achieve that throughput even in the worst case scenario—i.e., when a supply voltage of 2.6 V is provided. However, in many cases, the memory device may be used in an application that provides greater than the minimum supply voltage. It would be desirable in these scenarios to allow the memory device to take advantage of the increased supply voltage (and corresponding increase in charge pump current) to increase the throughput of the device.
Thus, what is needed is a memory device that allows throughput to vary with the power supply voltage.